Amicon® Ultra-4 centrifugal filter devices for protein purification and concentration provide fast ultrafiltration, with the capability for high concentration factors and easy concentrate recovery from dilute and complex samples . The vertical design and available membrane surface area provide fast sample processing, high sample recovery (typically greater than 90% of dilute starting solution), and the capability for 80-fold concentration. Solute polarization and subsequent contamination of the membrane are also minimized by the vertical design, and a physical deadstop in the filter device prevents spinning to dryness and potential sample loss. The concentrate is collected from the filter device sample reservoir using a pipettor, while the ultrafiltrate is collected in the provided centrifuge tube. The device can be spun in a swinging bucket (for optimal performance) or fixed angle rotor. Advantages: • High recovery Ultracel regenerated cellulose membrane in a range of molecular weight cut-offs • Vertical membrane reduces concentration polarization for ultra-fast spin times (as fast as 5 minutes) • Heat-sealed membrane minimizes downstream extractables • High retentate recovery of >90% • 100% integrity tested for reliable performance • Convenient sample monitoring with translucent housing and volume graduations • Direct pipette sample access eliminates processing step to recover concentrate • High concentration factors of 80-100X Applications: • Concentration of biological samples containing antigens, antibodies, enzymes, nucleic acids, or microorganisms • Purification of macromolecular components found in tissue culture extracts or cell lysates and protein removal prior to HPLC • Concentration of dilute or pre-purified proteins from column eluents • Desalting, buffer exchange, and protein dialysis • Size exclusion and protein fractionation Specifications: • Maximum initial sample volume – 4 mL (23? angle fixed rotor is 3.5 mL) • Typical final concentration volume – 50 µl • Centrifugal Force Swinging bucket rotor: 4,000 x g Fixed angle rotor: 7,000 x g for 3, 10, 30, and 50K; 5,000 x g for 100K • Active membrane area - 3 cm²